We have discovered five bismuth(III)-containing polyoxopalladates (POPs) which were fully characterized by solution and solid-state physicochemical techniques: the cube-shaped [BiPd12O32(AsPh)(8)](5-) (BiPd12AsL), [BiP12 O-32(AsC6H4N3)(8)](5-) (BiPd12AsLN), and [BiPd12O32(AsC6H4COO)(8)](13-) (BiPd12AsLC) as well as the star-shaped [BiPd15O40-(PO)(10)H-6](11-) (BiPd15P) and [BiPd15O40(PPh)(10)](7-) (BiPd15PL), respectively. The organically modified capping groups phenylarsonate, p-azidophenylarsonate, and p-carboxyphenylarsonate were chosen as the azido (-N-3) and carboxyl (-COOH) groups open up opportunities to covalently conjugate (via click reaction, amide coupling, etc.) with targeting vectors. The synthesis of p-azidophenylarsonate is reported here for the first time. The effects of the Bi ll1 template and the organoarsonate vs -posphonate capping groups on the resulting POP shape (cube vs star) are discussed. The Bi-209 NMR (I = 9/2) spectra of BiPd12AsL, BiPd12AsLN, and BiPd12AsLC revealed narrow peaks (nu(1/2) similar to 200 Hz) at 5470 ppm with a longitudinal relaxation time in the millisecond range (at 8.46 T). The absence of a quadrupolar relaxation contribution could be attributed to the allocation of BP in the highly symmetrical cuboid POP host cage. Similar peaks were absent in the Bi-209-NMR spectra of the star-shaped POPs BiPd15P and BiPd15PL due to the less symmetric coordination environment around the central Bi-III ion. Further, Bi-205/206-radiolabeled POPs have been synthesized by incorporating a Bi-205/206(III) ion in the center of the POP structures. Carrier-free Bi-205/206 radioisotopes (as surrogates of alpha-emitting Bi-213) were incorporated into the POP host-cage for the preparation of (BiPd12AsL)-Bi-205/206, (BiPd12AsLN)-Bi-205/206, (BiPd12AsLC)-Bi-205/206, and (BiPd15PL)-Bi-205/206, respectively. The radiometal incorporation was complete (>99% radio-chemical yield) in 10 min according to radio-thin-layer chromatography. The (BiPd12AsL)-Bi-205/206 polyanion was purified by solid-phase extraction. The incubation in rat serum showed the formation of a (BiPd12AsL)-Bi-205/206-protein aggregate.